Rumplestiltskin realised he made a mistake about the time he'd tossed her out. But by the time he was ready to admit that and go after her, she was long gone. Had she returned home, to her castle and father, fiance too? A quick trip to Avonlea, ghosted with an invisibility potion, told him otherwise.
And then, Regina came. Taunting him about how Belle had gone to her father's and then died by his hand. Grinding his teeth, Rumplestiltskin called upon his magic to test the truth of Regina's words and found hope and solace in the fact that Belle was most certainly alive.
Which meant Regina had imprisoned her. Angrily, Rumplestiltskin appeared in Regina's castle. "What," he shouted. "Have you done to her? Where is she?!" Regina tried to make excuses, tried to stick to the same story, but Rumple had none of it. After crushing Regina's heart, the dark one scoured her castle.
And then he saw her, beautiful, beautiful Belle. "Belle," he whispered, his voice a cracked, hoarse thing. Belle backed up, shaking her head in what he mistook to be fear. "No, get away from me! Rumplestiltskin, stop!" she shouted, slapping his hand away when he reached to touch her.
"You have to get out of here, sweetheart, come home. With me." Rumplestiltskin pleaded, trying once more in vain to reach out for her. Belle stepped back further into the corner of her dungeon. "You broke my heart. I won't go anywhere with you, thank you," she said as firmly as she could manage.
"We need to talk, Belle, but I promise - I love you." his voice was quiet, but a flinch was the telltale that Belle had indeed heard him. "F-Fine." she sighed, looking away as she let him take her hand. "Take me to the Dark Castle … but then we're talking." she threatened.